Enhanced Thermal Stability/Activity of Geobacillus jurassicus Esterase by Rational Design and Application in the Synthesis of Cinnamyl Acetate.

Abstract

Geobacillus sp. represents an important source of thermophilic esterases, yet studies on the rational design and industrial application of these enzymes remain limited. In our previous research, we identified the esterase Gju768 from Geobacillus jurassicus DSMZ 15726. In the present study, we employed a novel computer-aided rational design approach, ACDP (AutoDock, Consurf, Discovery Studio, PoPMuSiC), to enhance the enzyme's thermal stability. Through molecular docking and conservation analysis, three hotspots were identified. Virtual saturation mutagenesis was subsequently performed, yielding two selected mutations, Q78I and Q78L, from the resulting library. Notably, mutants Q78I and Q78L exhibited significant improvements in thermal stability and enzyme activity compared to the wild type (WT). Compared to WT, mutants Q78I and Q78L exhibited a 65.27% and 38.38% increase in half-life at 65 °C, along with a 14.48% and 1.60% improvement in specific activity at their respective optimal temperatures. Furthermore, under optimized conditions for cinnamyl acetate production, mutant Q78I demonstrated a yield of 68%, compared to only 31% for WT. This study underscored the potential of protein engineering strategies to enhance enzyme performance in industrial applications, particularly for the synthesis of value-added compounds such as cinnamyl acetate.